What do I do to eliminate this?
When I add variants that option repeats.
I need the variant to show once and when the product doesn't have the variant to show nothing.
What can I do? Do I need to edit the template?
Also, How can I add a personalization box so the customer can type the initials or message on the product.
Can you share your store link with us so we can see the problem, please?
For adding a personalization box, you can follow those Shopify instructions here:
<p class="line-item-property__field"> <label for="add-a-message">Add a Message</label> <input id="add-a-message" type="text" name="properties[Add a Message]"> </p>
Also, you can use this website to customize the option boxes You would like to add: